The invention relates generally to a system and method for replacing the original background of a digitally captured image with a new background. More specifically, the invention relates to the generation and application of a mask for replacing the background of an image.
Photographic scenes and their images may be divided into distinct parts on the basis of their importance to overall scene content. In every scene there is usually some part that represents the subject of major interest with the remaining parts providing context. Generally, parts in the foreground of a scene usually predominant over background parts, but this is not always so because there are obviously those cases where the background conveys information vital to an overall understanding of a scene's full information content. However, there are kinds of scenes where the background is really of little significance and may even detract from the foreground. Most of these involve scenes populated by one or more nearby humans where the background could be dispensed with altogether or otherwise rendered unobtrusive. Official settings demanded for passports, identification badges, and drivers licenses are but a few examples of this type of scene which are contrived to eliminate any influence a background may have on the subject.
To have an "official" photograph made typically requires a specially designed and lighted setting in a studio or photography shop. Here, a neutral featureless background is supplied to provide a uniform field against which the subject's face or upper body is photographed. While this procedure is not generally inconvenient, it is not as convenient as being photographed at a booth or kiosk designed for autophotography, where one can take one's own photograph.
With traditional autophotographic devices, the background and illumination of the studio setting is usually mimicked but without the disadvantage of relying on a professional photographer to take the actual "picture". More recently, autophotographic devices have been advocated which allow a subject to be photographed against some ambient background that can change, thus eliminating the need for providing a real controlled background. Instead, it is proposed that the scene be imaged, the foreground and background separated, and the original background replaced by a preferred one suitable for the official purpose at hand--all to be done via digital image processing techniques. Afterwards the new image may be reproduced in hard copy form.
The parent case to this application discloses the general approach for replacing the background of an image by differentiating between two infrared (IR) light illuminated images to distinguish between the foreground and background of the corresponding visible light image. It specifically discloses a background replacement method where two IR images with different intensities of IR illumination in the foreground and background regions of the scene, respectively, are compared for light intensity differences between corresponding pixels of the two images to form a mask differentiating between the foreground and background regions of the image. The mask is then applied to a visible light image of the scene and the original background is replaced with a preselected background.
The primary object of the present invention is the generation and application of a mask for use with the background replacement system and method of the parent case. This and other objects will become apparent in view of the following description, drawings and claims.